Baaaaaaaaad service from MTN

A very bad service i received from MTN, took a contract and canceled it within 4 days of receiving the router because I wasn't happy, the cancelation was never done and I was even debited, yet I was told the cancelation is done. Theres a refund due to me, but I being told call customer care, when I call them they refer me to billing department and billing department refer me back to customer care. This has been going on since November 2025. I do not know what to do because I'm still getting statements😡😡😡😡😡😡😡😡😡😡